Running a PC as a server has a quite significant hit on your bill:
it's
about the same as having a 100W bulb on all the time.
As to the X-10 gear, I
reckon you are down to the levels of a TV on
standby.
I
suppose the trick is to use occupancy detection, and smarter control of
things
such as the heating etc, to recoup that through more efficient
use.
Ian.